Separable casing for musical instruments



July 30, 1929. A. D. TRENOR 1,722,643

SEPARABLE CASING FOR MUSICAL INSTRUMENTS Original Filed 1925 2Sheets-Sheet 1 IIQQL llllllllllllIIIIIIIWIIIIII 1 III? 'z w- 19Pk/ENTER:

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July 30, 1929. A. D. TRENOR SEPARABLE CASING FOR MUSICAL INSTRUMENTSOrigingl Filed Nov. 30, 1925 2 Sheets-Sheet 2 w l w "W w ATTDRVNELFPatented July 30, 1929.

PATENT OFFICE.

ALBERT D. TRENOR, 0F GLOUCESTER, MASSACHUSETTS, ASSIGNOR TO JOHN HAYSHAMMOND, JR., OF GLOUCESTER, MASSACHUSETTS.

UNITED STATES SEPARABLE CASING FOB, MUSICAL INSTRUMENTS.

Application filed November 30, 1925, Serial No. 72,130. Renewed March22, 1929.

This invention relates to improvements in musical instruments and moreparticularly to improved means for controlling the emission of sound.

Broadly stated, it is one object of the present invention to provide animproved casing for a musical instrument of the pianoforte typeincluding means for effectively preventing passage of sound through thewalls of the piano, and thus reducing undesired leakage of musicalsound.

The invention also relates to the provision of an improved casing whichmay readily be removed, when desired, from the musical instrument forwhich it is adapted.

Other objects will appear from the following description taken inconnection with the accompanying drawings in which Figure 1 is a topplan view of so much of a piano and easing therefor as is necessary toan understanding of the invention.

Figure 2 is a front elevation partly in section of the structure ofFigure 1.

Figure 3 is a sectional view of one portion of the mechanism shown inFigure 2, taken on the line 33 of Figure 2.

Figure 4 is a cross section taken on the line 4-4 of Figure 1 and Figure5 is a transverse cross section showing details of the structure ofFigure 1.

Like reference characters refer to like parts in the several figures ofthe drawings.

In the following description and claims, parts will be identified by secific names for convenience of expression, ut they are intended to beas generic in their application to similar parts or equivalentconstruction as the art will permit. 7

Referring to the drawings and particularly to Figures land 2, there isshown a grand piano, including a fixed casing 10, having therein for thepurpose of producing sound, a plurality of tuned strings such as 11,tuned to the notes of the musicalscale. It will be understood that theremay be provided for each note of the musical scale one or more of suchstrings as may be required to produce the intensity of sound desired.The strings 11 are mounted'in the usual frame 12 in a conventionalmanner. For vibrating the strings of each of the notes'of the musicalscale by percussion there is provided a suitable hammer action as at 13,each operatively connected to one of the keys 11 respectively, of themanual of the piano. Be-

low the manual and in convenient position for the performer, there isprovided a pedal block 16 upon which there is positioned a plurality ofpedals shown three in number as at 17, 18 and 19. The two right handpedals as seen in Figure 2 are connected to the sustenuto and loud pedalactions of the piano in aconventional manner, and having no bearing onthe present invention it is thought they need not be further described.

The left hand pedal 17 is pivotally mounted in the block 16 and at itsrear end is pivotally connected to a vertical reciprocating rod 20,mounted in suitable bearings The upper end of the rod 20 engages one armof a pivoted bell crank lever 26, pivoted as at 27 to a fixed portion ofthe piano. A spring such as a leaf spring 28 is mounted on the casing ofthe piano and is arranged so that it normally maintains the bell cranklever and associated parts in the position illustrated in Figure 2 andrestores the parts to the position shown after displacement. Thearrangement is such that when the front end of the pedal 17 is depressedby the performer the rod 20 is raised and the bell crank lever 26 isrotated in a counter clockwise direction as seen in Figure 2. The otherarm of the bell crank lever 26 is OPGIatlXQlV con nected by means of aconnecting rod 30 to an arm 31 affixed to the lower end of a rotatableshaft 32.

The shaft 32 is rotatably mounted in spaced journal bearings 33 and 34which are secured to the fixed casing 10 of the piano. a collar 35 beingsecured to the shaft 32 to prevent longitudinal movement of the shaftwith respect to the bearings. The shaft 32 is provided with apair ofspaced arms 36 and 37 rotating therewith, the arm 36 being adjacent thelower face of the fixed casing 10, while the arm 37 is positioned nearthe upper face of the fixed casing 10. The outer ends of the arms 36 and37 are pivotally connect ed by means of a pair of connecting links 40,41, respectively, to a pair of connecting rods 42, 43.

An additional or separable casing structure is mounted upon the fixedcasing 10 and includes articulated sections such as 18, 49. As shown inFigure 4, each section comprises an upper moulding strip 50 and a lowermoulding strip 51, and the contour of these strips corresponds to theconfiguration of the fixed casing 10, (see Figure 1). The strips and 51are spaced apart-in a vertical plane and maintain in positionintermediate them a sheet of veneer 52. A narrowstrip of moulding 53 isprovided to cover the joint between the veneer 52 and the upper moulding50 and a similar narrow moulding strip 54 is provided for theCorresponding lower joint between the veneer 52 and the lower moulding51. On the inner face of the veneer 52 is mounted a strip of soundabsorbing material 55 such as felt or the like, and secured to the fixedcasing 10 are metal-plates 57, 58. At spaced intervals a plurality oflong machine screws such as 59, 60, are screwed through the narrowmoulding strip, veneer and insulating material into engagement with themetal plates 57, 58, thus securing the separable casing to the fixedcasing 10. At the rear of the piano, the two sections 48 and 49 arejoined as illustrated in Figure 5 of the drawings, and a strip ofmoulding 61 is provided for concealing this joint, and for holding thesections together.

The separable casing structure may be readily attached or detached fromthe fixed casing 10 of the piano by means of the machine screws 59, andthe two sections 48, 49 of the separable casing may thus be dismountedin a minimum time. then applied to the casing 10 the separablecasingserves to suppress the sound produced within the casing 10throughthe side walls of the piano.

The casing 10 is also provided with oppo sitely disposed apertures as at70,71. Mounted in the upper aperture is .a series of modulatingreflectors as at 72, therefor, thus forming controllable closures forthe apertures and serving to control the emission of sound; Eachreflector is preferably in the form of an elongated flat memberpivotally mounted to rotate about its longitudinal axis and is providedon its inner face with a sheet of sound reflecting material 73, such assheet aluminum or the like. Each reflector is provided with an arm 74,and the parts of the upper group of reflectors are pivotally connectedattheir outer ends with the upper connecting rod 43. Similarly there ismounted in the lower aperture 71 a second group of modulating reflectorsas at 75, serv ing to control the emission of sound through the lowerapertures. Each reflector is in the form of an elongated flat memberrotatable about its longitudinal axis and having on its upper inner facea sheet of sound reflecting material 76 such as sheet aluminum or thelike. Each reflector 75 is provided with an operating arm, the outer endof which is pivotally connected with the lower connecting rod 42.

In operation, when the separable casing is applied to the fixed casingas has been hereinbefore described, themanual of the piano may beoperated by a musician to cause vibration ofthe strings by percussion.In order arms forming to produce a desired efiiect the pedal 17 isdepressed to a desired extent. Downward movement of the pedal 17 causesthe rod 20 to be movedup wardly so as to rotate the bell crank lever 26against the tension offthe spring 28 in a counter clockwise direction asseen in Figure 2. The connecting link 30 and the connecting rods 42 and43 are thus moved towards the right and thus the reflectors 72 of theupper group of reflectors are rotated in a clockwise direction andthereflectors 75 of the lower group are rotated in a counter clockwisedirection. Assuming that the pedal 17 has been fully depressed, thereflectors are thus adjustedinto thefully closed position with therespective apertures closed. The compressional waves are thus reflectedback from the metal lined reflectors and the energy of the waves isimparted regeneratively to the strings, so that the vibration of thestrings is very greatly sustained. The sound is effectively preventedfrom emission through the side walls of the casing by means of theinsulating characteristics of the separable casing structure describedin connection with Figures 4 and 5. By thus insulating the instrument,the proportion of uncontrolled musical sound and of sound leaks is insuch ratio to the controlledsound, as to repre sent a relatively smallfraction of the minimum tone emitted from the instrument. Thus improvedshading and sensitive control of the musical dynamics are obtained.

' When it is desired to emit a portion of the sound produced by thestrings the pressure is partly taken oil the pedal 17 and the spring 28causes the pedal and associated parts to be retractedto the extentdesired by the musician. The reflectors 72 and 75 arethus caused to bepartially opened and an increase in the amount of musical sound emittedfrom the instrument is obtained. Whenit is desired to emit a stillgreater proportion of the sound the pedal 17 is moved'upwardly to astill greater degree and the volume of emitted sound is thereby furtherincreased. The reflecting surfaces 73 and 76 greatly improve the controlof the tone with respect to the listener. V

The invention upon which this application is based is broader than thespecific embodiment showg and described for the purpose ofillustrating-at least one of the ways in which it may be employed. Thescope of the invention is therefore to be'understood as not beinglimited by the present specific description. I intend no limitationsother than those imposed by the claims.

What is claimed is:

1. In a'musical instrument, the combination with means for producingsound by percussion, a fixed casing surrounding said means andhaving'oppositely disposed apertures for the emission of musical sound,and boundary walls intermediate said apertures,

of a separable casing arranged to be mounted upon said boundary walls.

2. In a musical instrument, the combination with means for producinvsound by percussion, a fixed casing surrounding said means havingoppositely disposed apertures, for the emission of musical sound, andboundary walls intermediate said apertures, of a substantially soundproof casing demountably secured to said intermediate walls forsuppressing sound transmitted through said intermediate walls.

3. In a musical instrument, the combination with tuned strings forproducing musical sound, a fixed casing surrounding said strings andincludin apertured walls and an imperforate wall, 0% a separable casingarranged to be mounted upon said imperforate wall.

4. In a musical instrument, the combination with means for producingsound by percussion, a fixed casing having oppositely disposedapertures, and an imperforate wall, of a substantially sound proofcasing demountably secured to said imperforate walls.

5. In a musical instrument, the combination with a vibratory element,and a percussive action for striking said element to produce dampedcompressional waves, of a fixed casing surrounding said element, aseparable casing structure supported by the fixed casing, said separablecasing including two spaced mouldings having the configuration of thefixed casing and a sheet of sound absorbent material supported betweensaid mouldings and in spaced relation with the wall of the fixed casing.

6. In a musical instrument, the combination with a vibratory element,and a percussive action for striking said element to produce dampedcompressional waves, of a fixed casing surrounding said element, aseparable casing structure supported by the fixed casing, said separablecasing including two spaced mouldings having the configuration of thefixed casing, each of the mouldings being formed in sections, means forsecuring the sections together, and a sheet of sound absorbent materialsupported between said mouldings and in spaced relation with the wall ofthe fixed casing.

7. In a musical instrument, the combination with a tuned string, and ahammer for striking said string to produce damped compressional waves,of a fixed casing surrounding said string, and a separable casingstructure supported by the fixed casing, said sep arable casingincluding articulated mouldings having the configuration of the fixedcasing and a sheet of sound absorbent material supported on saidmouldings and in spaced relation with the wall of the fixed casing.

8. In a piano, a fixed casing havin apertures, a plurality of modulatingre ectors positioned in said apertures for variably controlling soundemitted therethrough, a plurality of plates aflixed to the fixed casing,a separable casing including a layer of sound insulating material,demountably positioned on the fixed casing, and a plurality of holdingscrews passing through the insulating material and engaging said platesrespectively.

9. In a piano, a fixed casing, a plurality of modulating reflectors forcontrolling the musical sound emitted, a separable casing structuredemountably secured to the fixed casing and comprising a pair of spacedmouldings a sheet of sound insulating material supported between saidmouldings and spaced apart from the wall of the fixed casing, and aprotective covering for said material supported on the mouldings, andreadily removable means for fastening the separable casing structure tothe fixed casing.

Signed at New York in the county of New York and State of New York, thistwentyseventh day of November, A. D. 1925.

ALBERT D. TRENOR.

